Submission #384674

#	Time	Username	Problem	Language	Result	Execution time	Memory
384674		anachor	Aliens (IOI16_aliens)	C++14	0 / 100	2 ms	384 KiB

aliens

#include<bits/stdc++.h>
using namespace std;

const int N = 1e5+7, K = 55;

long long cost(int l, int r, int *x, int *y, long long c) {
//    cout<<l<<" "<<r<<" "<<c<<" "<<y[r]<<" "<<x[l]<<" "<<(y[r] - x[l])*(y[r] - x[l]) + c<<endl;
    return 1LL*(y[r] - x[l])*(y[r] - x[l]) + c;
}

typedef pair<long long, long long> PLL;
PLL dp[N];

PLL operator+(PLL a, PLL b) {
    return PLL(a.first+b.first, a.second+b.second);
}

long long opt[N];
int x[N], y[N];

PLL check(long long c, int n, int *x, int *y) {
    deque<pair<int, int>> dq;
    dq.push_back({0, 1});
    dp[0] = {0, 0};

    for (int i=1; i<=n; i++) {
        opt[i] = dq.front().first;
        dp[i] = dp[opt[i]] + PLL(cost(opt[i]+1, i, x, y, c), 1);
//        cout<<i<<" --> "<<opt[i]<<" "<<dp[i].first<<endl;
        dq[0].second++;
        if (dq.size() > 1 && dq[0].second == dq[1].second)  dq.pop_front();

        int en = n;
        while(dq.size()) {
            int o = dq.back().first, st = dq.back().second;
            if (dp[o]+PLL(cost(o+1, st, x, y, c), 1) >= dp[i]+PLL(cost(i+1, st, x, y, c), 1))  dq.pop_back();
            else {
                int lo = st, hi = en;
                while (lo < hi) {
                    int mid = (lo+hi+1)/2;
                    if (dp[o]+PLL(cost(o+1, mid, x, y, c), 1) < dp[i]+PLL(cost(i+1, mid, x, y, c), 1) )   lo = mid;
                    else                                                hi = mid-1;
                }
                if (lo < n) dq.push_back({i, lo+1});
                break;
            }
            en = st-1;
        }
        if (dq.empty()) dq.push_back({i, i+1});
    }
//    cout<<c<<" "<<dp[n].first<<" "<<dp[n].second<<endl;
    return dp[n];
}

long long take_photos(int n, int N, int k, vector<int> xx, vector<int> yy) {
    vector<pair<int, int>> ranges;
    for (int i=0; i<n; i++) {
        ranges.push_back({max(xx[i], yy[i]), -min(xx[i], yy[i])});
    }
    sort(ranges.begin(), ranges.end());

    vector<pair<int, int>> r2;
    for (auto pr: ranges) {
        int r = pr.first, l = -pr.second;
        while (r2.size() && r2.back().first >= l)   r2.pop_back();
        r2.push_back({l, r});
    }

    n = r2.size();
    for (int i=1; i<=n; i++) {
        x[i] = r2[i-1].first, y[i] = r2[i-1].second+1;
    }

    long long lo = -1e12, hi = 1e12;
    while (lo < hi) {
        long long mid = lo + (hi-lo)/2;
        if (check(mid, n, x, y).second > k)      lo = mid+1;
        else                            hi = mid;
    }
    return check(lo, n, x, y).first - k*lo;
}

• Subtask 1: 0 / 4
• Subtask 2: 0 / 12
• Subtask 3: 0 / 9
• Subtask 4: 0 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 40